Electrolytic cell



E. A. ALLEN ELECTROLYTIC CELL.

APPLICATION FILED DEC.19,' 191a.

1 35 1,886, Patented Sept. 7 1920,

UNITED STATES EDWARD A. ALLEN, OF PORTLAND, MAINE.

ELECTROLYTIC CELL.

Application filed December 19, 1918.

To all whom it may concern Be it known that I, EDWARD A. ALLEN, a citizen of the United States, residing at Portland, in the county of Gumbel-land and State of Maine, have invented new and useful Improvements in Electrolytic Cells, of which the following is a specification.

The present invention has relation to an electrolytic cell, and in the embodiment which is chosen for the present illustration the cell is designed to produce the chlorate of sodium or potassium by electrolysis of a salt solution. This statement, however, is not intended to indicate a limitation in the scope of the protection which I claim, but simply to illustrate a particular use to which the invention may be applied. It is to be. understood that the principles and features pointed out in the following claims are protected as my invention in every use and adaptation to which they may be put.

Amongother objects designed to be ac compli'shed by the invention are the carry. ing on of the electrolytic process with maximum efficiency and with great economy in the expenditure of current; the elimination of deterrent efiects in the accomplishment of the operation through the action of nascent hydrogen which occurs as one of the inevitable by-products of the electrolysis; efficient insulation of the electrodes one from the other; making the casing of the cell serve as the cathode of the electrolytic couple; enabling carbon bars or slabs to be used as the anode or anodes of the cell; and provision for an economical use of the carbon anode with minimum waste of material.

The precise nature of the invention appears from the following detailed description of an embodiment of the invention which for certain reasons I consider preferable to other possible forms, in connection with drawings illustrating. such embodiment. In the drawings,

Figure 1 is an end elevation of the cell here referred to. Fig. 2 is a plan view of the cell. Fig. 3 is a longitudinal section on an enlarged scale taken on line 3-3 of Figs. 1

and 2. Fig. 4 is a plan view of a modified construction containing means for mounting discontinuous anode sections in a single chamber of the cell. Fig. 5 is a perspective view of the lower end of one of the insulating supports for the anodes. Fig. 6 is a similar view of a form of support used in Specification of Letters Patent.

Patented Sept. 7, 1920.

Serial No. 267,462.

the construction illustrated in Fig. at. Fig. 7 is a vertical section on a further enlarged scale illustrating a detail of one of the corners of the cell.

Like reference characters designate the same parts wherever they occur in all the figures.

The form of cell here illustrated consists of a-casing or shell a which is made of metal in order that its walls may serve as the cathode of the electrolytic couple; and preferably it is provided with partitions b and c dividing it into separate and distinct compartments or chambers e, f, and g. Preferably the casing or shell is made as a castmg, of which the wall, bottom, and partitions 6 and c are integral parts, and preferably also the metal of which it is made is cast iron, although other metals may be used and other modes of manufacture may be practised. Also I may make it without the interior partitions as a single chamber cell, although for various reasons that will appear later, it is preferable to make it with a number of compartments as here shown. The partitions terminate below the rim of the casing, whereby flow of electrolyte from one chamber to another may take place by overflowing the partitions, and preferably there is no other communication between the chamber than that occurring by Each compartment contains an anode, the several anodes being represented in Figs. 1, 2, and 3 as h, 7: and Z. All of these anodes are connected in parallel to the positive busbar or other lead of the electric circuit, by any means suitable for the purpose, such means not being illustrated in these drawings as they are familiar to those acquainted with the art. The casing or shell is, of course, suitably connected with the negative lead of the circuit. These anodes are preferably made of carbon. As concerns certain aspects of the invention it is essential that they be made of this material, but in other aspects this characteristic is not essential, but other material having sufiicient electrical conductivity and being sufiiciently inert to the chemical and electrocheanical effect of the electrolyte may be use The anode in each compartment is supported and held out of contact with the walls and bottom of the compartment by insulating supports m, one of which is shown in detail in perspective view in Fig. 5. These supports are bars of insulating material formed to fit the corners of the casing between a side and end wall and between the side wall and partitions, and having a lengthwise channel a at the inner corner shaped to embrace one of the corners of the anode. In the form here shown the insulating support is substantially a square prism and the channel is rectangular with its walls perpendicular to the sides of the prism which they intersect. This form, however, is a minor feature and may be varied without departing from the invention. The

essential characteristics are only that the insulator should be adapted to reside against a'wall' of the chamber and should confine and hold a part of the anode, and provided this ,essential is present it is unimportant what the precise form of the insulator and its channel may be. The channel may terminate short of the lower end of the insulator in a shoulder 0 on which the bottom of the anode rests. When such connectors are placed in each of the corners of the chamber, resting on the bottom, and the anode is inserted with its corners occupying the channels of the insulators, then the anode is supported above the bottom and clear of all of the walls of the chamber which it occupies, leaving spaces on all sides and beneath it to be filled by electrolyte, and insulated from such walls. I have used slate as material for making these insulators, but I do not restrict my claim for protection to such material, as I may use porcelain, glass, vulcanite,

or any other insulating material which is adapted to be made into a bar having the essential characteristics herein noted. Preferably I provide on the bottom of each compartment an insulating plate 1) of glass or other suitable material, having an area and dimensions more or less nearly equal to the bottom of the compartment, and on which the insulators m rest. This plate is provided in order to prevent establishment of a short circuit and an arc between the anode and a point on the casing, due to the accumulation of sediment. In a cell of this character sediment which is electrically conductive is apt to settle in the bottom of the case, and troublehas been experienced in the past from a short circuit taking place through an accumulation of such sediment with formation of an arc and consequent'loss of efliciency and damage. The insulating plate 79 prevents any such result.

A porous screen 9 is provided to lie against or near the walls of the several com partments; in other words, the outer walls of the casing and the opposite sides of the partitions. This screen is made of some material which is freely permeable by the electrolyte and is at the same tim not affected thereby or by the electric current. I prefer to use asbestos cloth for this purpose, employing a continuous strip which is substantially the full width of the cell and is sufficiently long to extend the full height of the outer walls, up and down the opposite sides of each of the partitions, and across the bottoms of the compartments. This screen is fitted into the empty casing or shell before insertion of any of the other, parts hereinbefore described, and after being so fitted, the insulating plates are placed in the bottoms of the several compartments over those lengths of the screen which cross such bottoms, and when the anode supports are placed in the corners of the compartment, and the anodes are inserted in engagement with the supports. Thus the insulating members retain the screen or screens in place against or close to'the wall surfaces of the several compartments. The purpose of such screen or screens is to confine hydrogen gas which is liberated by electrolysis of solutions containing hydrogen in combination, such for example as the aqueous solutions of sodium chlorid and potassium chlorid used for producing chlorates, and to cause the liberated hydrogen to rise and escape from the top of the cell without recombining} The effect desired to be avoided thereby will be understood from the following explanation. An early effect of electrolysis on sodium chlorid solution, for example, is the formation of sodium hydrate and hydrogen according to the following equation:

Further reaction occurs, with production of sodium hypochlorite, as follows:

The hydrogen thus liberated is in nascent condition and is highly active, whereby it tends strongly to recombine with the oxygen atom of the hypochlorite, the latter compound being relatively unstable; thus neutralizing to a considerable extent the electrolytic effect. But by providing a screen or screens in the manner above stated the 'liber-' ated hydrogen-is confined in close proximity to the cathode portions of the cell and is prevented from passing through theelectrolyte,

whereby it is caused to escape into the atalthough this is not absolutely necessary, since these walls form only a minor part of the total wall surface of the compartments.

It will have been apparent from the foregoing description that one of the characteristics of the cell is the provision of massive anodes having large surface area in contact with electrolyte, and narrow spaces to contain electrolyte between the adjacent surfaces of the anodes and cathodes. Another feature is that the single cell may have a more or less large number of anodes all connected up in parallel in the electric circuit. In practice I have found that with the use of a cell made as hereinbefore described I am able to pass currents of large amperage through the cell under comparatively low electromotive force, that is, I am able to secure results in the output of the final product equal or superior to the results obtained by the electrolytic cell heretofore made for the purpose, with expenditure of electrical energy not exceeding one-half of that generally required in theprior forms of cells.

In the use of the cell with carbon anodes for the specific purpose hereinbefore pointed out, there is a consumption of the anode material by oxidization of the carbon, resulting in the liberation of carbonic acid and the wasting away of the anodes. One feature of the invention consists in provisions for economically utilizing anodes after they have been partially consumed in this manner. For this purpose I make compart ments of different. widths, and use in the first or widest of the compartments anode pieces of standard size and thickness. Then as the anodes become reduced in bulk I shift them from the largest compartment to the one of next smaller width, after first truing the surfaces to fit the space provided for its reception in that compartment; and at the same time transfer the partially consumed carbon from the second compartment, after truing its surfaces in like manner, to the third compartment, which is of still less width; and so on, depending on the number of compartments in the cell. By way of specific illustration I would say that in the three compartment cell illustrated here, the first compartment 6 is designed to accommodate an anode having a thickness of two inches, the second compartment f one hav ing a thickness of one and one-half inches, and a third compartment 9 one having a thickness of one inch; in other words, the ratios of the several anodes are as four to three to two; and the same principle may be extended either up or down, or both up and down, in cells having a greater number of compartments In this way a single anode piece may be used until it is so far consumed by use as to be no longer serviceable; that is, for example, one of a thickness of two inches may be continuously used until its thickness is reduced to less than one inch before it needs to be discarded as waste material. lVhen the anode piece is diminished in width as well as thickness by use, provision may be made for its accommodation in successive chambers either by making the chambers likewise of less length as well as width, or by appropriately shaping and proportioning the insulating supports in the different chambers so that they will hold anode pieces of progressively diminishing widths. I have illustrated the feature last described in Fig. 2, where the supports m and m in the compartments and g are shown as being proportioned to support anodes of progressively less width,

In Fig. at I have illustrated means for using anode pieces of standard dimensions in cells of different volumetric capacities. For various reasons it is desirable to manu facture the anode blocks of standard dimensions, which may, for example, be fifteen inches in length by seven inches width by two inches thickness. A cell having an over all width of eight inches is adapted to contain anodes of the width here given; but it is sometimes desirable to make the unit cell of greater capacity than that, wherefore I have provided means by which it may be made to mount in each compartment two, three, or more of the standard anodes, or such anodes after they have been diminished in width by the action previously explained. I do this by furnishing intermediate insulating supports 9", one of which is shown in detail in Fig. 6; such anode supports being bars in general similar to the supports m, but cut away at two of the adjacent corners to form two longitudinal channels 8 and 6 adapted to receive the adjacent corners of anodes a and a or a and a These channels likewise terminate at their lower ends in supporting shoulders u and '0, respectively, similar to the shoulder 0. Substantially similar intermediate supports 1' and r are provided in the compartments containing 70, it, etc. and Z, Z, Z etc.

In the foregoing description I have considered the length of the cell as that dimension extending in the direction of the line 33 of Fig. 2, and the width of the cell as a whole as the dimension at right. angles thereto; but I have considered the width of the single compartment as the shorter dimension of the compartment, which is the dimension in the same .direction as the length of. the entire cell, while the length of the individual compartment is correspondingly considered as its greater dimension.

In the use of the cell having the characteristics hereinbefore described to produce chlorate from a solution of common salt or potassium chlorid, the operation or process is carried out as a continuous one, fresh electrolyte being continuously admitted at one end of the cell and the changed electrolyte being continuously withdrawn from the other end. The rate of supply of the fresh solution is regulated to allow the temperature of the electrolyte to rise to the degree which favors the most efiicient production of the chlorate, and to subject the solution to electrolytic action for as long a time as will efficiently produce that content of chlorate which favors most efficient extraction of the chlorate from the solution. Under such conditions of operation, subsequent cooling of the delivered electrolyte causes the chlorate to be crystallized out of the solution.

I have not deemed it necessary to explain in detail the reactions which take place in the course of the electrolyzing process, as such reactions are well known and understood by those acquainted with the art. I have deemed it sufficient for the purposes of explaining my present invention to point out that when applied to the particular use of producing chlorates, it effects this result in an improved manner and with economy of energy and electrode material as compared with the cells heretofore used. I wish to emphasize also that I do not restrict the protection claimed herein to an electrolytic cell for that particular purpose, but claim as my invention all novel features and characteristics of the cell whatever may be the use to which it is applied or adapted.

WVhat I claim and desire to secure by Letters Patent is:

1. An electrolytic cell comprising an outer casing or shell of metal having an inner space containing electrolyte, and being itself the cathode of the electrolytic couple, supporting and insulating bars adapted to fit against the walls within the casing and having channels, and an anode piece fittingthe channels of said bars and positioned thereby out of contact with the walls of the casing.

2. An electrolytic cell comprising an outer casing or shell of metal having an inner space containing electrolyte, and being itself the cathode of the electrolytic couple, supporting and insulating bars adapted to fit against the walls within the casing and 'having channels, and an anode piece fitting the channels of said bars and positioned thereby out of contact with the walls of the casing, the channels in said bars terminating short of the lower ends of the bars and leaving shoulders which support the anode above the bottom of the compartment in which it resides.

An electrolytic cell comprising a metallic casing forming the cathode, an anode occupying the interior of said casing, an insulating plate on the bottom of the space within the casing which the anode occupies,

and insulating means holding said anode out of contact with the surfaces of the casing.

4. An electrolytic cell comprising a casing having walls of conducting material arranged to provide a compartment for electrolyte having distinct angles or corners, prismatic insulating bars fitting the corners of said compartment and having channels, and an anode having dimensions adapting it to enter said compartment and occupy said channels, whereby it retains the insulating bars in place and is itself insulated from said walls.

5. An electrolytic cell comprising a casing having interior transverse partitions providing a number of compartments, the walls and partitions of said casing being of electrically conductive material and forming a cathode, anodes occupying the several compartments, and insulating means holding the anodes within the several compartments out of contact with the walls thereof.

6. An electrolytic cell comprising a casing having interior transverse partitions providing a number of compartments, the walls and partitions of said casing being of electrically conductive material and forming a cathode, anodes occupying the several compartments, and insulating means holding the anodes within the several compartments out of contact with the walls thereof, the different compartments being of progressively diminishing widths, whereby to enable the same anode to be progressively placed in one compartment after another as it becomes diminished in bulk by use.

7. An electrolytic cell comprising a casing having walls of'conducting material forming a cathode and adapted to contain electrolyte, an anode occupying the interior of said casing, means for holding said anode out of contact with, said conducting walls, and screens permeable by the electrolyte arranged close to said walls to prevent nascent hydrogen produced by electrolytic action from mingling with the electrolyte.

8. An electrolytic cell comprising a casing having walls of conducting material forming a cathode and adapted to contain electrolyte, an anode occupying the interior of said casing, means for holding said anode out of contact with said conducting walls, and screens permeable by the electrolyte arranged close to said walls to prevent nascent hydrogen produced by electrolytic action from mingling with the electrolyte, said screens being formed and arranged to permit escape of hydrogen upwardly between them and the contiguous walls from the top of the cell.

9. An electrolytic cell comprising a casing having walls of conducting material arranged to form a compartment adapted to contain electrolyte, screens permeable by the tudinal angles of an anode, and an anode in said compartment arranged with its angles occupying such channels, being held by the insulating bars separated on all sides from the walls of the compartment, and retaining the insulating bars in place, the latter in turn holding the screens in place.

10. An electrolytic cell comprising a metallic shell'having intermediate transverse parallel partitions also metallic and dividing the material of the casing into a number of compartments, a flexible porous sheet of inert material disposed to lie against the opposite sides of the partitions and against the inner sides of the end Walls of the casing and extending over the bottoms of said compartment, insulating bars occupying the corners of the compartments and bearing against those portions of said sheet which extend along the adjacent walls, and anodes occupying said compartments in contact with said insulating bars holding the latter and the lengths of the sheet in place, and being itself held away from all the walls of the compartment.

11. An electrolytic cell comprising a casing forming a chamber adapted to contain electrolyte, an anode in sections occupying said chamber, and means for supporting said anode sections out of contact with the walls of the chamber comprising bars occupying the corners of the chamber having channels to receive the corners of the endmost electrode sections, and intermediate bars arranged against opposite walls of the chamber, each having two channels arranged to receive the corners of two ad acent anode sectlons.

12. An insulating Supporting bar for an electrode, said bar having a generally prismatic form with one of its corners or longitudinal angles cut away or channeled to form an inwardly extending groove.

18. An insulating supporting bar for an electrode, said bar having a generally prismatic form with one of its corners or longitudinal angles cut away or channeled to form an inwardly extending groove, such groove terminating short of one end of, the

bar and leaving a shoulder at its termination.

14. A support and insulator for the purpose indicated comprising a bar of insulating material having a longitudinal groove adapted to receive the corner of the electrode.

15. A support and insulator for the purpose indicated comprising a bar of insulating material having two parallel longitudinal grooves adapted to receive the corners of two adjacent sections of an electrode.

16. An insulator for the purpose indicated comprising a generally prismatic bar having two of its corners cut away and recessed to provide parallel longitudinal channels adaptedto admit the corners of adjacent sections of an electrode.

17. An insulator for the purpose indicated comprising a generally prismatic bar having two of its corners cut away and recessed to provide parallel longitudinal channels adapted to admit the corners of adjacent sections of an electrode, said channels terminating short of one end of the bar and being bounded by shoulders adapted to support such sections.

In testimony whereof I have aflixed my signature.

EDWARD A. 

